1. Field of the Invention
The present invention relates to a power hand tool, and more specifically to a gyration/reciprocating action switching mechanism for a power hand tool, which shortens the spread of axles of the output shaft of the power hand tool, enabling the axial length of the power hand tool to be minimized for convenient holding of the hand.
2. Description of the Related Art
U.S. Pat. No. 5,711,380 discloses a rotate percussion hammer/drill shift device suitable for hand drill. The device is disposed at an output spindle of a drill to provide the drill with a percussion function. It comprises a stationary percussion cam, an output shaft that is connected to the output spindle of the drill in a coaxial manner wherein the output shaft can be selectively moved to a working position from a normal position. This output shaft further includes a rotary cam by which the output shaft may rotate synchronously with the spindle of the drill, and a clutch mechanism which retains the output shaft in the normal position and permits the output shaft to be moved to the working position. The percussion cam is in contact with the rotary cam, which is rotating such that the rotary cam generates a periodical hammer movement in the axial direction. Consequently, the output shaft is provided with a hammer movement. This design is functional. However, because this design is comprised of a great number of parts, its manufacturing cost is high, and its assembly procedure is complicated. Because of huge dimension and heavy weight, the user cannot hold the power hand tool for a long time.